The boat's guest of honor, U.S. Interior Secretary Ken Salazar, rose to laud his hosts and to assure them that his country was taking steps to "get our act together" on offshore wind power.

"We see Denmark as a leader and an example in wind, especially offshore," Salazar told a cabin filled mostly with European journalists and wind-energy officials. "We know we have a tremendous way to go."

Denmark draws more than 20% of its electricity from wind, the highest percentage in the world and one envied by U.S. officials eager to boost production of renewable energy.

His hastily organized harbor tour helped launch a weeklong charm offensive by the Obama administration at the international climate negotiations in Copenhagen, a push to sell world government and business leaders on the United States' increased commitment to renewable energy and combating climate change.

In public, at least, there appears to be a long way to go, as evidenced in part by an exchange Wednesday between representatives of the U.S. and China.

The United States' special climate envoy, Todd Stern, urged China to honor its pledge to reduce its carbon emissions and to include that commitment in an international climate change agreement. China's chief climate negotiator, Yu Qingtai, not only rejected the idea, he also criticized the U.S. for failing to provide financial aid to developing countries and reduce its own emissions of harmful gases.

Such sentiment toward the U.S. was anticipated. While Salazar was motoring through waters shrouded in gray, Environmental Protection Agency Administrator Lisa Jackson briefed reporters and activists on the administration's efforts to curb greenhouse gas emissions unilaterally. She touted the administration's declaration this week that those gases endanger human health and are thus subject to regulation under the Clean Air Act.

Stern also emphasized the EPA action during an afternoon news conference, along with the U.S. economic stimulus dollars devoted to renewable energy. "The United States' commitment is strong," he said, adding later, "It's an aggressive package that the president has put down."

A parade of Cabinet-level secretaries will repeat that theme in the coming days, including the secretaries of Agriculture, Energy and Commerce, along with the head of the White House Council on Environmental Quality and the president's top advisors on science and climate change.

Environmental groups say the effort appears to be winning support from diplomats who have worried aloud in recent weeks that the administration's action has not matched its lofty rhetoric. But those groups say only President Obama can deliver the assurances that the rest of the world needs to complete a new emission-reduction treaty.

"What they're going to need to hear from the president next week," said Alden Meyer, director of strategy and policy for the Union of Concerned Scientists, "is that it is going to be his priority to push [a climate bill] through the Senate after healthcare."

Salazar, a former senator from Colorado, told his maritime audience that a climate bill that limited carbon emissions would accelerate his efforts to encourage offshore wind farms on the Outer Continental Shelf managed by the Interior Department. The United States does not currently have such farms.

He commended the Danes for their goal to produce half their power from wind in coming years, while acknowledging that Obama's goal -- 25% from renewable sources, including wind and solar, by 2025 -- is much more modest.